Hashi

Background

Hashi is short for <em>Hashiwokakero,</em> 橋をかけろ, that is, "Build Bridges". It was invented by Nikoli and first published in 1989.

Puzzle and Goal

An unsolved puzzle consists of terminal points distributed at some of the vertex points of an unseen rectangular grid, containing numbers from 1 to 8.

The goal is to connect the terminal points.

Rules

The solved grid must satisfy the following conditions:

Each terminal point shows the total number of segments ending at that point.

At most two segments connect any two points.

Segments are horizontal or vertical.

Segments do not cross other segments.

All terminal points are interconnected.

Variants

Variations include allowing more than two lines between pairs of terminal, having larger terminals (which therefore have more than four possible connection points), and encrypting clues (such that "A" always represents the same number, etc.).